Concept question The following stress-strain curves were obtained for dif- ferent materials subjecting the specimen to the loading path(a, b, c, d ). Which one(s) of them correspond to elas- tic material(s) (1)and(2) 2 (3) (2)and(4) None of the above DKDU++++ ++++ ++++ ++++ ++++ Concept Question ++++ ++++ ++++ ++++ ++++ The following stress-strain curves were obtained for dif￾ferent materials subjecting the specimen to the loading path (a,b,c,d). Which one(s) of them correspond to elas￾tic material(s)? b c d d b c d b c d σ ε σ ε σ ε σ ε a a a a (1) (2) (3) (4) b c 1. ++++ (1) and (2) 2. ++++ (3) 3. ++++ (2) and (4) 4. ++++ None of the above 5. ++++ DKDU